Scholarly Works, Fish and Wildlife Conservation

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  • Antibiotic Susceptibility of non-pathogenic Escherichia coli from meat and produce available in the Chobe region of Botswana
    Saunders, Rachel; Bywater, Auja L.; Fleming, Madison; Kelly, Christine; Nuckolls, Evan; Alexander, Kathleen A.; Ponder, Monica A. (2023-04-21)
  • Enabling regulatory policy globally will promote realization of the potential of animal biotechnology
    Hallerman, Eric M.; Bredlau, Justin; Camargo, Luiz S. A.; Dagli, Maria L. Z.; Karembu, Margaret; Kovich, Daniel; Muia, Anne N.; Murrone, Mariana L.; Rocha-Salavarrieta, Pedro J.; Romero-Aldemita, Rhodora; Tizard, Mark; Walton, Mark; Wray-Cahen, Diane (2024-03-06)
    Animal biotechnologies have the potential to improve the sustainability and security of our global food systems. Government regulatory authorities are responsible for ensuring the safety of food their citizens consume, whether it is produced via conventional breeding methods or biotechnologies. While some countries have implemented animal biotechnology oversight policies, many countries have yet to develop theirs. Historically, regulatory approvals were required before products of biotechnology could enter the marketplace, and the high cost of the approval process limited the number and types of animal and plant products that sought approval. Only one biotech animal in the world that was developed for food production has reached the market under a GMO or rDNA approval process. The advent of genome editing techniques has revolutionized the scientific approach to introducing changes into DNA sequences and how biotechnology can be used to enhance agricultural breeding. Regulatory dialogs about biotechnology also have changed as a result of these new technologies. Regulatory agencies have begun to respond to these scientific advances, and a growing number of countries are looking to modernize regulatory approaches for these products, based on risk (or lack thereof) and similarity to organisms that could be produced via conventional breeding methods. Advances in animal biotechnology, especially genome editing, can accelerate the incorporation of valued phenotypes in animals, including enhanced yield, disease resistance, resilience to changing climate, and improved animal welfare, as well as food qualities valued by consumers. For animals with these biotechnology-introduced traits to enter agricultural production and reach consumers, clear risk-proportionate regulatory approaches must be in place, and to facilitate international trade of animal products, regulatory processes need to be aligned and compatible. Effective scientific public communication is crucial to build public trust in precision animal biotechnology and risk-proportionate regulatory approaches. An international workshop on regulatory approaches for animal biotechnology was convened in 2022 with 27 countries represented. We synthesize here technical progress, development of regulatory policy, and strategies for engagement with diverse publics on animal biotechnology reported in the workshop. Our goal is to encourage development and implementation of risk-proportionate regulatory approaches and policies in a global context.
  • Population Genetic Differentiation of Walleye (Sander vitreus) across the Eastern Highlands of the United States
    Harris, Sheila C.; Palmer, George; Stepien, Carol A.; Hallerman, Eric M. (MDPI, 2023-12-29)
    Walleye is an important sportfish across eastern North America, is commercially fished in the Laurentian Great Lakes region, and has been introduced outside its native range. Thirty-eight Walleye populations within six watersheds across the Eastern Highlands and other portions of the native range were screened at eight microsatellite DNA loci to better understand evolutionary history and to inform fishery management and conservation efforts. Population genetic variation showed divergent assemblages of populations, respectively, living in the Mobile Bay, Mississippi River, Eastern Highlands (Tennessee, New, and Ohio Rivers), and Great Lakes drainages today. All estimates of effective numbers of breeding individuals were under 25, and all populations within all watersheds had ~15–20% inter-individual relatedness, likely attributable to the effects of both natural demographic processes and stocking. The extent of Eastern Highlands Walleye includes both the Ohio and Tennessee River basins.
  • Shark detection and classification with machine learning
    Jenrette, Jeremy; Liu, Zac; Chimote, Pranav; Hastie, Trevor; Fox, Edward; Ferretti, Francesco (Elsevier, 2022-07-01)
  • Influences of Satellite Sensor and Scale on Derivation of Ecosystem Functional Types and Diversity
    Liu, Lingling; Smith, Jeffrey R.; Armstrong, Amanda H.; Alcaraz-Segura, Domingo; Epstein, Howard E.; Echeverri, Alejandra; Langhans, Kelley E.; Schmitt, Rafael J. P.; Chaplin-Kramer, Rebecca (MDPI, 2023-12-01)
    Satellite-derived Ecosystem Functional Types (EFTs) are increasingly used in ecology and conservation to characterize ecosystem heterogeneity. The diversity of EFTs, also known as Ecosystem Functional Diversity (EFD), has been suggested both as a potential metric of ecosystem-level biodiversity and as a predictor for ecosystem functioning, ecosystem services, and resilience. However, the impact of key methodological choices on patterns of EFTs and EFD have not been formally assessed. Using Costa Rica as a study system, we compared EFTs and EFD, derived from MODIS and Landsat data using different methodological assumptions, at both national and local extents. Our results showed that the regional spatial patterns of EFTs and EFD derived from 250 m MODIS and 30 m Landsat are notably different. The selection of sensors for deriving EFTs and EFD is dependent on the study area, data quality, and the research objective. Given its finer spatial resolution, Landsat has greater capacity to differentiate more EFTs than MODIS, though MODIS could be a better choice in frequently cloudy areas due to its shorter revisiting time. We also found that the selection of spatial extent used to derive EFD is critical, as smaller extents (e.g., at a local rather than a national scale) can show much higher diversity. However, diversity levels derived at smaller extents appear to be nested within the diversity levels derived at larger extents. As EFTs and EFD continue to develop as a tool for ecosystem ecology, we highlight the important methodological choices to ensure that these metrics best fit research objectives.
  • Birds are not the only ones impacted by guidance to cease bird feeding
    Dayer, Ashley A.; Pototsky, P. Christy; Hall, Richard J.; Hawley, Dana M.; Phillips, Tina B.; Bonter, David N.; Dietsch, Allan M.; Greig, Emma; Hochachka, Wesley M. (Wiley, 2023)
    1. Humans have a particularly strong connection with birds, driving the enormous popularity of residential bird feeding in much of the world. 2. We conducted a web search to document US state wildlife management agency responses to two recent avian disease outbreaks, finding that 23 agencies made recommendations to cease feeding wild birds in 2021–2022. 3. The psychological benefits of bird feeding for humans are well-documented but often overlooked in management decisions in response to avian disease outbreaks. 4. Likewise, ecological evidence does not necessarily support ceasing bird feeding to reduce the spread of every avian disease. 5. Ecological and social science need to be applied in tandem to ensure that well-intended guidance to cease feeding of birds does not have unintended consequences.
  • Climate change linked to vampire bat expansion and rabies virus spillover
    Van de Vuurst, Paige; Qiao, Huijie; Soler-Tovar, Diego; Escobar, Luis E. (Wiley, 2023-10)
    Bat-borne pathogens are a threat to global health and in recent history have had major impacts on human morbidity and mortality. Examples include diseases such as rabies, Nipah virus encephalitis, and severe acute respiratory syndrome (SARS). Climate change may exacerbate the emergence of bat-borne pathogens by affecting the ecology of bats in tropical ecosystems. Here, we report the impacts of climate change on the distributional ecology of the common vampire bat Desmodus rotundus across the last century. Our retrospective analysis revealed a positive relationship between changes in climate and the northern expansion of the distribution of D. rotundus in North America. Furthermore, we also found a reduction in the standard deviation of temperatures at D. rotundus capture locations during the last century, expressed as more consistent, less-seasonal climate in recent years. These results elucidate an association between D. rotundus range expansion and a continental-level rise in rabies virus spillover transmission from D. rotundus to cattle in the last 50 years of the 120-year study period. This correlative study, based on field observations, offers empirical evidence supporting previous statistical and mathematical simulation-based studies reporting a likely increase of bat-borne diseases in response to climate change. We conclude that the D. rotundus rabies system exemplifies the consequences of climate change augmentation at the wildlife–livestock–human interface, demonstrating how global change acts upon these complex and interconnected systems to drive increased disease emergence.
  • Genetic Structure across Isolated Virginia Populations of the Endangered Candy Darter (Etheostoma osburni)
    McBaine, Kathryn E.; Angermeier, Paul L.; Hallerman, Eric M. (MDPI, 2023-10-01)
    Candy darter Etheostoma osburni, a federally endangered non-game fish, has been extirpated from most of its historic range in Virginia and now occurs in four isolated populations in the New River drainage. Understanding of population genetic structure will provide insights into the recent natural history of the species and can inform conservation management. Our objectives were to: characterize population genetic structure, estimate and compare effective population sizes (Ne), and use this information to infer recent population history. Variation at mitochondrial cytochrome b sequences among 150 individuals showed 10 haplotypes separated by 1–14 mutational steps, some shared and some unique to particular populations. Variation at 12 microsatellite loci among 171 individuals showed lower variation in Dismal Creek than in other populations. All populations showed evidence of having experienced a genetic bottleneck and were highly differentiated from one another based on both types of DNA markers. Population genetic structure was related to stream position in regard to the New River, suggesting that populations were once connected. Ne estimates for all populations were less than the 500 recommended to maintain evolutionary potential, but most estimates were greater than the 100 needed for use as source populations. Our findings indicate that habitat management to allow expansion of populations, and translocations to exchange genetic material among populations, may be effective tactics to promote conservation of candy darter in Virginia.
  • Coursing hyenas and stalking lions: The potential for inter- and intraspecific interactions
    Barker, Nancy A.; Joubert, Francois G.; Kasaona, Marthin; Shatumbu, Gabriel A.; Stowbunenko, Vincent; Alexander, Kathleen A.; Slotow, Rob; Getz, Wayne M. (Public Library of Science, 2023-02)
    Resource partitioning promotes coexistence among guild members, and carnivores reduce interference competition through behavioral mechanisms that promote spatio-temporal separation. We analyzed sympatric lion and spotted hyena movements and activity patterns to ascertain the mechanisms facilitating their coexistence within semi-arid and wetland ecosystems. We identified recurrent high-use (revisitation) and extended stay (duration) areas within home ranges, as well as correlated movement-derived measures of inter- and intraspecific interactions with environmental variables. Spatial overlaps among lions and hyenas expanded during the wet season, and occurred at edges of home ranges, around water-points, along pathways between patches of high-use areas. Lions shared more of their home ranges with spotted hyenas in arid ecosystems, but shared more of their ranges with conspecifics in mesic environments. Despite shared space use, we found evidence for subtle temporal differences in the nocturnal movement and activity patterns between the two predators, suggesting a fine localized-scale avoidance strategy. Revisitation frequency and duration within home ranges were influenced by interspecific interactions, after land cover categories and diel cycles. Intraspecific interactions were also important for lions and, important for hyenas were moon illumination and ungulates attracted to former anthrax carcass sites in Etosha, with distance to water in Chobe/Linyanti. Recursion and duration according to locales of competitor probabilities were similar among female lions and both sexes of hyenas, but different for male lions. Our results suggest that lions and spotted hyenas mediate the potential for interference competition through subtle differences in temporal activity, fine-scale habitat use differentiation, and localized reactive-avoidance behaviors. These findings enhance our understanding of the potential effects of interspecific interactions among large carnivore space-use patterns within an apex predator system and show adaptability across heterogeneous and homogeneous environments. Future conservation plans should emphasize the importance of inter- and intraspecific competition within large carnivore communities, particularly moderating such effects within increasingly fragmented landscapes.
  • Campylobacter in aquatic and terrestrial mammals is driven by life traits: A systematic review and meta-analysis
    Brooks, Michael R.; Medley, Sarah; Ponder, Monica A.; Alexander, Kathleen A. (Frontiers, 2023-02)
    Introduction: Campylobacter spp. infections are responsible for significant diarrheal disease burden across the globe, with prevalence thought to be increasing. Although wild avian species have been studied as reservoirs of Campylobacter spp., our understanding of the role of wild mammalian species in disease transmission and persistence is limited. Host factors influencing infection dynamics in wild mammals have been neglected, particularly life traits, and the role of these factors in zoonotic spillover risk is largely unknown. Methods: Here, we conducted a systematic literature review, identifying mammalian species that had been tested for Campylobacter spp. infections (molecular and culture based). We used logistic regression to evaluate the relationship between the detection of Campylobacter spp. in feces and host life traits (urban association, trophic level, and sociality). Results: Our analysis suggest that C. jejuni transmission is associated with urban living and trophic level. The probability of carriage was highest in urban-associated species (p = 0.02793) and the most informative model included trophic level. In contrast, C. coli carriage appears to be strongly influenced by sociality (p = 0.0113) with trophic level still being important. Detection of Campylobacter organisms at the genus level, however, was only associated with trophic level (p = 0.0156), highlighting the importance of this trait in exposure dynamics across host and Campylobacter pathogen systems. Discussion: While many challenges remain in the detection and characterization of Camploybacter spp., these results suggest that host life traits may have important influence on pathogen exposure and transmission dynamics, providing a useful starting point for more directed surveillance approaches.
  • An approach to assess data-less small-scale fisheries: examples from Congo rivers
    Castello, Leandro; Carvalho, Felipe; Ateba, Nelly Ornelle Onana; Busanga, Alidor Kankonda; Ickowitz, Amy; Frimpong, Emmanuel (Springer, 2023-03)
    Small-scale fisheries (SSF) account for much of the global fish catch, but data to assess them often do not exist, impeding assessments of their historical dynamics and status. Here, we propose an approach to assess 'data-less' SSF using local knowledge to produce data, life history theory to describe their historical multispecies dynamics, and length-based reference points to evaluate stock status. We demonstrate use of this approach in three data-less SSFs of the Congo Basin. Fishers' recalls of past fishing events indicated fish catch declined by 65-80% over the last half-century. Declines in and depletion of many historically important species reduced the diversity of exploited species, making the species composition of the catch more homogenous in recent years. Length-at-catch of 11 of the 12 most important species were below their respective lengths-at-maturity and optimal lengths (obtained from Fishbase) in recent years, indicating overfishing. The most overfished species were large-bodied and found in the Congo mainstem. These results show the approach can suitably assess data-less SSF. Fishers' knowledge produced data at a fraction of the cost and effort of collecting fisheries landings data. Historical and current data on fish catch, length-at-catch, and species diversity can inform management and restoration efforts to curb shifting baselines of these fisheries. Classification of stock status allows prioritizing management efforts. The approach is easy to apply and generates intuitive results, having potential to complement the toolkits of researchers and managers working in SSF and engage stakeholders in decision-making processes.
  • Comparing estimates of census and effective population size in an endangered amphibian
    Brooks, George C.; Wendt, A.; Haas, Carola A.; Roberts, J. H. (Wiley, 2023-03)
    The field of conservation has seen a shift in focus from monitoring trends in census population size to trends in `effective' population size. Numerous genetic methods exist for estimating effective population size, resulting in uncertainty among conservation practitioners as to which methods are most appropriate when conducting population assessments or evaluating recovery efforts. Demographic approaches offer a promising avenue to provide a link between census and effective population size using life-history information, but rarely do studies have all three sources of data (genetic, demographic, life history) necessary to perform an explicit evaluation of their performance. Using data from a long-term study of reticulated flatwoods salamanders (Ambystoma bishopi) in western Florida, USA, we assessed the magnitude of temporal variation in census population sizes oNTHORN and the effective number of breeders Nbo THORN of two breeding populations to (1) document changes in the number of breeding adults over the 9-year study duration, (2) determine whether N and Nb provide similar information about population size and trends and (3) compare alternative demographic and genetic approaches for estimating Nb. We found that genetic estimates of bN b, particularly if averaged across multiple estimation methods, closely tracked spatiotemporal variation in N. Demographic estimates of Nb also closely tracked N but were sensitive to the assumed variance in reproductive success. In the absence of genetic information, detailed knowledge of mating systems and the environmental factors that skew reproductive contributions appear necessary for demographic Nb to reliably inform management decisions. In these populations, bN b appears too small (<40 individuals) to confer long-term genetic resilience, highlighting the importance of restoring landscape connectivity and indicating that caution must be taken when sourcing animals for reintroduction efforts. More generally, our study reveals insights into the utility of alternative Nb estimation methods in guiding recovery efforts of threatened and endangered species.
  • Quantifying longline bycatch mortality for pelagic sharks in western Pacific shark sanctuaries
    Shea, Brendan D.; Gallagher, Austin J.; Bomgardner, Lindsay K.; Ferretti, Francesco (American Association for the Advancement of Science, 2023-08)
    Marine protected areas are increasingly touted for their role in conserving large marine predators such as sharks, but their efficacy is debated. Seventeen “shark sanctuaries” have been established globally, but longline fishing continues within many such jurisdictions, leading to unknown levels of bycatch mortality levels. Using public data from Global Fishing Watch and Regional Fisheries Management Organizations, we quantified longline fishing within eight shark sanctuaries and estimated pelagic shark catch and mortality for seven pelagic shark species. Sanctuary mortality ranged from 600 individuals (Samoa) to 36,256 individuals (Federated States of Micronesia), equivalent to ~5% of hypothesized sustainable levels for blue sharks to ~40% for silky sharks, with high mortality levels in the Federated States of Micronesia, Palau, and the Marshall Islands. Unsustainable mortality rates were exceeded for silky sharks in two sanctuaries, highlighting a need for additional stock assessments and implementation of bycatch reduction measures. Big data integration workflows represent a transformative tool in fisheries management, particularly for data-poor species.
  • Conservation Genetics of Clinch Dace Chrosomus sp. cf. saylori
    Bourquin, Rebecca M.; Moore, Michael J.; Orth, Donald J.; Hallerman, Eric M. (MDPI, 2023-07-13)
    Clinch Dace (Chrosomus sp. cf. saylori) is a newly recognized and yet-undescribed species of minnow with a restricted and fragmented distribution in the upper Tennessee River basin in southwestern Virginia, USA. We collected Clinch Dace from seven streams and observed variations at nine selectively neutral microsatellite DNA loci to infer population genetic processes and identify units for conservation management. Bayesian cluster analysis showed that three of the seven surveyed populations were genetically distinct, while the other four populations showed signs of recent admixture. Estimated effective population sizes and m-ratios were low within most populations, suggesting loss of alleles due to recent genetic drift. Positive FIS values, high average individual inbreeding coefficients, and high degrees of inferred relatedness among individuals suggested that inbreeding is taking place in some populations. FST values were high, and analysis of molecular variance indicated genetic divergence among populations. These indicators suggest that Clinch Dace populations are subject to the genetic processes that are characteristic of small and isolated populations.
  • Environmental Complexity and Reduced Stocking Density Promote Positive Behavioral Outcomes in Broiler Chickens
    Evans, Lauren; Brooks, George C.; Anderson, Mallory G.; Campbell, Andrew M.; Jacobs, Leonie (MDPI, 2023-06-23)
    The objective was to evaluate the impacts of a complex environment and stocking density on Ross 708 broiler chicken behaviors. Eight pens contained either high complexity (HC) or low complexity (LC) environments, and high (HD) or low (LD) density. Through focal-animal sampling, the frequency and duration of behaviors were recorded continuously for 5 min at two timepoints for one day in weeks 2, 4, and 7. Birds were active for 30% of the observed time, with birds showing more activity in HC compared with LC. Birds in HC pens spent more time preening and foraging than birds in LC pens, which was interpreted as a positive outcome. Dustbathing and play were not impacted by complexity, possibly due to the observation method. Birds were more frequently active at HD compared with LD, but did not spend more time being active, suggesting disturbances. Birds foraged, drank, and ate less frequently in HD compared with LD, presumably because birds had more difficulty accessing resources. Activity and active behaviors reduced as birds aged, while preening frequency increased, possibly due to frustration, but this was not confirmed. Perching was unaffected by age, showing a persistent motivation to perform the behavior. Our results indicate that a complex environment provides positive stimulation for foraging, locomotion, preening, and overall activity. Despite reduced activity, many benefits of the tested environmental complexity and low density persisted as birds aged.
  • Utah Results of the Wildlife Viewer Survey: Enhancing Relevancy and Engaging Support from a Broader Constituency
    Sinkular, Emily N.; Pausley, Emma R.; Pototsky, Christy; Dayer, Ashley A. (Virginia Tech, 2023-07-07)
    Wildlife viewing is among the fastest growing outdoor recreation activities in the United States, with significant implications for the work of wildlife agencies. While important insights have emerged piece-meal from a number of surveys, agencies lack generalizable information about wildlife viewers (those who intentionally observe, feed, or photograph wildlife; travel to parks, protected areas, or other natural spaces with the purpose of feeding, observing, or photographing wildlife, and those who maintain plantings or natural areas for the benefit of wildlife) behaviors, experiences, perceptions, needs, and preferences. This information is essential for more meaningful and substantive engagement for state agencies with this often underserved constituency. Through a 2021 AFWA MultiState Conservation Grant, Virginia Tech and the AFWA Wildlife Viewing and Nature Tourism Working Group conducted national and state level surveys to gather more data on wildlife viewers. This report contains results from the survey in Utah. This work was funded by U.S. Fish and Wildlife Service’s Multistate Conservation Grant Program (grant # F21AP00617-00) and Utah Department of Natural Resources.
  • A Synthesis of the Ecology and Conservation of Pseudoplatystoma Catfishes in the Neotropics
    Pereira, Luciana A.; Castello, Leandro; Orth, Donald J.; Duponchelle, Fabrice; Hallerman, Eric M. (MDPI, 2023-06-07)
    Species of the genus Pseudoplatystoma, the long-whiskered catfishes, are important in commercial and recreational fisheries in South America, and some species have become key to regional aquaculture. Some species of the genus are under pressure due to overfishing and the negative impacts of dams. Six questions are asked in this review: (i) What species are in the genus, and where are they distributed? (ii) What are the life histories and ecologies of Pseudoplatystoma species? (iii) What are the patterns of somatic growth for these species? (iv) What is known about the biomass, production, and population dynamics of Pseudoplatystoma? (v) What is the geographic distribution of genetic variation within Pseudoplatystoma species? (vi) What are the threats to the conservation of these species? The taxonomy of the genus currently includes eight species, respectively, distributed over the Orinoco, Amazon, Paraná, and São Francisco basins. Pseudoplatystoma catfishes typically exhibit longitudinal migrations for reproduction and lateral migration for feeding, but these patterns may vary among populations. The size of the first maturation of these catfishes varies between 57 cm to 82 cm in total length. Five of the eight species spawn during the rising water season. Pseudoplatystoma species can grow to about 130 cm in total length and 100 Kg in weight and live until 30 years of age, depending upon the species. Biomass production and population dynamics of these catfishes have not yet been fully described. Their life-history characteristics indicate that they are periodic strategists with associated population recruitment dynamics. Population genetic patterning varies among Pseudoplatystoma species, with some degree of homing behavior and genetic differentiation among populations, indicating the need for management by applying the Management Unit and perhaps Evolutionary Significant Unit concepts. The main threats to the persistence of these catfishes are overfishing and alterations in and obstruction of river flow due to the construction of hydropower dams. After synthesizing existing information on species of the genus Pseudoplatystoma, we offer suggestions for future research to fill critical gaps in the knowledge of this group.
  • Draft Genome Sequences of 158 Listeria monocytogenes Strains Isolated from Black Bears (Ursus americanus) in the United States
    Brown, Phillip; Chen, Yi; Ivanova, Mirena; Leekitcharoenphon, Pimlapas; Parsons, Cameron; Niedermeyer, Jeffrey; Gould, Nicholas; Strules, Jennifer; Mesa-Cruz, J. Bernardo; Kelly, Marcella J.; Hooker, Michael J.; Chamberlain, Michael J.; Olfenbuttel, Colleen; DePerno, Christopher; Elhanafi, Driss; Kathariou, Sophia (American Society for Microbiology, 2023-06)
    Listeria monocytogenes is responsible for severe foodborne disease and major economic losses, but its potential reservoirs in natural ecosystems remain poorly understood. Here, we report the draft genome sequences of 158 L. monocytogenes strains isolated from black bears (Ursus americanus) in the southeastern United States between 2014 and 2017. Listeria monocytogenes is responsible for severe foodborne disease and major economic losses, but its potential reservoirs in natural ecosystems remain poorly understood. Here, we report the draft genome sequences of 158 L. monocytogenes strains isolated from black bears (Ursus americanus) in the southeastern United States between 2014 and 2017.
  • Fall migration, oceanic movement, and site residency patterns of eastern red bats (Lasiurus borealis) on the mid-Atlantic Coast
    True, Michael C.; Gorman, Katherine M.; Taylor, Hila; Reynolds, Richard J.; Ford, W. Mark (2023-06-14)
    Along the mid-Atlantic coast of the United States, eastern red bats (Lasiurus borealis) are present during fall mating and migration, though little is currently known about most aspects of bat migration. To reveal migration patterns, and understand drivers of over-water flight, we captured and radio-tagged 115 eastern red bats using novel technology, and subsequently tracked and described their movements throughout the region. We compared over-water flight movements to randomly generated patterns using a use-availability framework, and subsequently used a generalized linear mixed effects model to assess the relationship of over-water flight to atmospheric variables. We used hidden Markov models to assess daily activity patterns and site residency. Most bats with long-distance movements traveled in a southwesterly direction, however path vectors were often oriented interior toward the continental landmass rather than along the coastline. We observed that some bats transited wide sections of the Chesapeake and Delaware bays, confirming their ability to travel across large water bodies. This over-water flight typically occurred in the early hours of the night and during favorable flying conditions. If flight over large water bodies is a proxy for over-ocean flight, then collision risk at offshore wind turbines – a major source of migratory bat fatalities – may be linked nightly to warm temperatures that occur early in the fall season. Risk, then, may be somewhat predictable and manageable with mitigation options linking wind-energy operation to weather conditions and seasonality.